EuroSCORE overestimates the cardiac operative risk

Introduction: It was the purpose of our study to assess the validity of EuroSCORE (European system for cardiac operative risk evaluation) in our patient population. Materials and Methods: Between March 1999 and August 2001, information on risk factors and mortality was collected for 1123 consecutive adult patients undergoing heart surgery with cardiopulmonary bypass. EuroSCORE was used for risk stratification. Mean age ± standard deviation was 58.6 ± 10.9 and 29.1% of the patients were female. The area under the receiver operating characteristic (ROC) curve was calculated as an index for the predictive value of the scoring system. Results: The area under the ROC curve was 0.824 for all patients and 0.828 for the isolated CABG subgroup which shows an excellent predictive ability.When the scoring system was applied in low, medium, and high risk groups, there was no overlap between 95% confidence intervals of observed and expected mortality in all three groups both for the isolated CABG cases and for all patients. Decreased left ventricular ejection fraction, emergent operation, and preoperative unstable angina requiring i.v. nitrate treatment were significant predictive variables for early mortality. Conclusion: EuroSCORE is a simple and objective system for predicting the risk of heart surgery. The predictive power of the EuroSCORE is excellent, however it seems that mortality is considerably overestimated by this score.